I believe you can do the same thing by going into your Keyboard Shortcut dialog and added a shortcut to rotate the canvas. Click Edit > Keyboard Shortcuts. In the list, find Image, click the arrow to the left of the word and scroll down until you find Image Rotation. Select the entry for Arbitrary and add a shortcut. I found ALT+CNTRL+SHIFT+U and ALT+CNTRL+SHIFT+W were free (all variations with R are used elsewhere).